A Status Report on Chiral Dynamics: Theory and Experiment

This paper gives an overview of a Workshop on Chiral Dynamics: Theory and Experiment which was held at MIT July 25-29, 1994; its unique feature was the equal mixture of theory and experiment. The purpose of the workshop was to bring together many of the active participants to assess the status of the field and to explore fruitful future directions. The foundations and present status of the theory were reviewed as well as the experimental status of the field. To facilitate the discussion of future directions working groups were organized on Threshold Photo/Electropion Production, Two-Pion Threshold and the Chiral Anomaly, Nucleon Polarizabilities, Pion and Sigma Polarizabilities, $\pi-\pi$ Interactions, and $\pi$-N Interactions; these subjects were the focus of the experimental aspects of the workshop.Comment: 15 page standard TeX fil

Electrical characterization of polymeric insulation by electrically stimulated acoustic wave measurements

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1990.Includes bibliographical references (leaves 207-211).by Joseph Barry Bernstein.Ph.D

Design and fabrication of a vertical power MOSFET with an integral turn-off driver

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERINGBibliography: leaf 76.by Joseph Barry Bernstein.M.S

Impact of intentionally injected carbon dioxide hydrate on deep-sea benthic foraminiferal survival

Author Posting. © The Authors, 2009. This is the author's version of the work. It is posted here by permission of Blackwell for personal use, not for redistribution. The definitive version was published in Global Change Biology 15 (2009): 2078-2088, doi:10.1111/j.1365-2486.2008.01822.x.Sequestration of carbon dioxide (CO2) in the ocean is being considered as a feasible mechanism to mitigate the alarming rate in its atmospheric rise. Little is known, however, about how the resulting hypercapnia and ocean acidification may affect marine fauna. In an effort to understand better the protistan reaction to such an environmental perturbation, the survivorship of benthic foraminifera, which is a prevalent group of protists, was studied in response to deep-sea CO2 release. The survival response of calcareous, agglutinated, and thecate foraminifera was determined in two experiments at ~3.1 and 3.3 km water depth in Monterey Bay (California, USA). Approximately five weeks after initial seafloor CO2 release, in situ incubations of the live-dead indicator CellTracker Green were executed within seafloor-emplaced pushcores. Experimental treatments included direct exposure to CO2 hydrate, two levels of lesser exposure adjacent to CO2 hydrate, and controls, which were far removed from the CO2 hydrate release. Results indicate that survivorship rates of agglutinated and thecate foraminifera were not significantly impacted by direct exposure but the survivorship of calcareous foraminifera was significantly lower in direct exposure treatments compared to controls. Observations suggest that, if large scale CO2 sequestration is enacted on the deep-sea floor, survival of two major groups of this prevalent protistan taxon will likely not be severely impacted, while calcareous foraminifera will face considerable challenges to maintain their benthic populations in areas directly exposed to CO2 hydrate.This work was funded by the Monterey Bay Aquarium Research Institute (project 200002; to JPB), US Department of Energy grant # DE-FG02-03ER63696 (to J. P. Kennett and J.M.B.), and NSF OCE-0725966 (to J.M.B.)

The utility of thromboelastography in the monitoring of aspirin therapy

To assess the utility of the Thromboelastogram in monitoring of aspirin therapy 25 healthy volunteers were selected and given low-dose aspirin therapy. Thromboelastography and platelet aggregometry were conducted at baseline and 1 week later. After 1 week of aspirin therapy, TEG data failed to demonstrate a significant change in the clotting profile. Platelet aggregometry identified significant changes in the clotting profile in response to stimulation with arachodonic acid, adrenaline and ADP We conclude that thromboelastography may not have utility in monitoring of response to aspiri

Searching for the Kuhnian moment : the Black-Scholes-Merton formula and the evolution of modern finance theory

The Black-Scholes-Merton formula has been put to widespread use by options traders because it provides a means of calculating the theoretically 'correct' price of stock options. Traders can therefore see whether the market price of stock options undervalues or overvalues them compared with their hypothetical Black-Scholes-Merton price, before choosing to buy or sell options accordingly. As a consequence of this close relationship between options pricing theory and options pricing practice, a strong performativity loop was activated, whereby market prices quickly converged on the hypothetical Black-Scholes-Merton prices following the dissemination of the formula. The theory has therefore had significant real-world effects, but how should we characterize the initial instinct to derive the theory from a philosophy of science perspective? The two books under review suggest that a Kuhnian reading of the advancement of scientific knowledge might well be the most appropriate. But, on closer inspection, it becomes clear that the publication of the Black-Scholes-Merton formula should not be seen as a Kuhnian moment with paradigm-shaping attributes. It is shown that, at most, the formula acts as an important exemplar which, via its use in the training of options pricing theorists and options pricing practitioners, reinforces the entrenchment of finance theory within the orthodox economics worldview

Neutral Pion Lifetime Measurements and the QCD Chiral Anomaly

A fundamental property of QCD is the presence of the chiral anomaly, which is the primary component of the $\pi^0\rightarrow\gamma\gamma$ decay amplitude. Based on this anomaly and its small ($\simeq$ 4.5%) chiral correction, a firm prediction of the $\pi^0$ lifetime can be used as a test of QCD at confinement scale energies. The interesting experimental and theoretical histories of the $\pi^0$ meson are reviewed, from discovery to the present era. Experimental results are in agreement with the theoretical prediction, within the current ($\simeq$ 3%) experimental error; however, they are not yet sufficiently precise to test the chiral corrected result, which is a firm QCD prediction and is known to $\simeq$ 1% uncertainty. At this level there exist experimental inconsistencies, which require attention. Possible future work to improve the present precision is suggested.Comment: 75 pages, 17 figure

The First Detections of the Extragalactic Background Light at 3000, 5500, and 8000A (III): Cosmological Implications

(Abridged) We have used HST WFPC2 and ground-based spectroscopy to measure the integrated extragalactic background light (EBL) at optical wavelengths. We have also computed the integrated light from individual galaxy counts in the images used to measure the EBL and in the Hubble Deep Field. We find that the flux in galaxies as measured by standard galaxy photometry methods has generally been underestimated by about 50%. Further, we find that the total flux in individually detected galaxies is a factor of 2 to 3 less than the EBL at 3000--8000A. We show that a significant fraction of the EBL may come from normal galaxies at z<4, which are simply undetectable as a result of K-corrections and cosmological surface brightness dimming. This is consistent with recent redshift surveys at z<4. In the context of some simple models, we discuss the constraints placed by the EBL on the evolution of the luminosity density at z>1. Based on our optical EBL and published UV and IR EBL measurements, we estimate that the total EBL from 0.1--1000 microns is 100+/-20 nW/m^2/sr. If the total EBL were produced entirely by stellar nucleosynthesis, then we estimate that the total baryonic mass processed through stars is Omega_* = 0.0062 (+/- 0.0022) h^{-2}, which corresponds to 0.33+/-0.12 Omega_B for currently favored values of the baryon density. This estimate is smaller by roughly 7% if 7 h_{0.7} nW/m^2/sr of the total EBL comes from accretion onto central black holes. This estimate of Omega_* suggests that the universe has been enriched to a total metal mass of 0.21(+/-0.13) Z_sun Omega_B. Our estimate is consistent with other measurements of the cumulative metal mass fraction of stars, stellar remnants, and the intracluster medium of galaxy clusters in the local universe.Comment: Accepted for publication in ApJ, 20 pages using emulateapj.sty, version with higher resolution figures available at http://www.astro.lsa.umich.edu/~rab/publications.html or at http://nedwww.ipac.caltech.edu/level5/Sept01/Bernstein3/frames.htm

Prostate Cancer and Race

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72215/1/j.1525-1497.2003.30801.x.pd

Mapping replication dynamics in Trypanosoma brucei reveals a link with telomere transcription and antigenic variation

Survival of Trypanosoma brucei depends upon switches in its protective Variant Surface Glycoprotein (VSG) coat by antigenic variation. VSG switching occurs by frequent homologous recombination, which is thought to require locus-specific initiation. Here, we show that a RecQ helicase, RECQ2, acts to repair DNA breaks, including in the telomeric site of VSG expression. Despite this, RECQ2 loss does not impair antigenic variation, but causes increased VSG switching by recombination, arguing against models for VSG switch initiation through direct generation of a DNA double strand break (DSB). Indeed, we show DSBs inefficiently direct recombination in the VSG expression site. By mapping genome replication dynamics, we reveal that the transcribed VSG expression site is the only telomeric site that is early replicating – a differential timing only seen in mammal-infective parasites. Specific association between VSG transcription and replication timing reveals a model for antigenic variation based on replication-derived DNA fragility